Synchronizing clutch mechanism



Dec. 7, 1937. E. A. THOMPSON SYNCHRONIZING CLUTCH MECHANISM Fi'led Nov. 9, 1935 2 Sheets-Sheet l Dec. 7, 1937.

E. A. THOMPSON 2,101,826V SYNCHRONIZING CLUTCH MECHNISM Filed Nov. 9, 1955 2 sheets-sheet 2 Patented Dec. 7, 1937 UNITED STATES SYNCHEONIZDIG CLUTCH MECHANISM Earl A. Thompson, Birmingham, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application November 9, 1935, Serial No. 48,971

6 Claims.

This invention relates to synchronizing clutch mechanism associated with change-speed gearing particularly adapted for motor vehicle power transmission mechanisms.

'Ihe object is to enable toothed coupling elements to be intermeshed without clash, when changing from one gear train to another of different ratios, by rst synchronizing the velocities of the elements to be intermeshed.

The invention comprises coaxial, selective, positive clutches, combined with friction clutches adapted to synchronize the velocity of the positive clutches prior to interengaging them, said clutches constituting elements of a change speed gear mechanism.

More particularly the invention comprises: Two movable friction clutch elements connected by pins, rods, bars or equivalent angularly spaced members extending parallel with the main axis of the transmission and passing through openings formed in a double-ended slidable positive coupling element, said coupling element and said spaced connecting members having cooperating checking means adapted to resist coupling of the positive clutch elements until synchronization has been eiected by the friction clutch elements.

In the accompanying drawings wherein like reference characters indicate like parts throughout the several views,

Fig. 1 is an elevation of a transmission casin partly broken away and exposing inclosed change vgear mechanism;

Fig. 2 is a detail of the control mechanism for changing gear ratios taken on line 2-2 of Fig. l;

Fig. 3 is a fragmentary section on line 3-3 of Fig. 1;

Fig. 4 is a section on line 4-4 of Fig. 1;

Fig. 5 is a diagrammatic view of one pair of checking elements in transverse section, and

Fig. 6 is a diagrammatic view of the elements shown in Fig. 5, but in longitudinal instead of transverse section.

In the drawings numeral i2 indicates a transmission casingy of a form not substantially different from those in common use in motor vehicles. The upper side of the casing is closed by a removable cover I3'having the usual hollow towerlike riser I4 in which the gear shift lever H4 is fulcrumed.- 'I'he power-delivery end of the main clutch shaft 28 enters the forward end of the casing and, asusual, rotates in a bearing (not shown) in the casing. The end of the main clutch shaft 20 within the casing is equipped with the usual counter shaft driving gear 22, which has integrally or otherwise rigidly joined to its rear face (Cl. 19E-53) the transmission mechanism to operate in third or high speed.

A main driven shaft 30, commonly designated the spline shaft in motor vehicle nomenclature, is disposed in axial alinement with main clutch shaft 20, which is provided with an axial bore in its rear end in which the reduced forward end 32 of the spline shaft is piloted. The rearward end of shaft 30 passes through the rear wall of the transmission casing i 2 and is as usual mounted in bearings (not shown) in the casing.

Countershaft driving gear 22 meshes with a gear 40 rigid on countershaft 42, which has also rigidly connected to it, a gear 44 of the second speed train, a gear 46 of the first speed train, and a gear 48 of the reversing train. Gear 48, it will be understood, is, as usual, in mesh with a reverse-train idler gear (not shown).

, A gear 50 slidably keyed on shaft 80 may be slid forward to mesh with countershaft gear 46, whereupon rst speed coupling of the gear set is established through gears 22, 40, 46 and 58. Gear 50 may be slid rearward into mesh with the reverse idler whereupon reverse-drive coupling of the gear set is established through gears 22, 40,48, reverse idler and gear 50.

Gear 52 is mounted coaxial with spline shaft 38 on a bearing member 54 secured to the shaft so as to rotate with it. Said bearing has an integral iiange 56 at one end and a separable flange 58 secured at the other end. Snap rings 59 or the like prevent axial movement of the bearing member 54 on shaft 30. Flanges 56 and 58 prevent axial movement of gear 52 with respect to bearing member 54. Gear 52 is in constant mesh withcountershaft gear 44, and is a part of the second speed train. It rotates freely on bearing member 54 unless locked to shaft 30 by means to be described.

Gear 52 is formed with an annular forwardreaching adjunct 24a similar to the adjunct 24 on gearf22. Adjunct 24a carries internal gear-like clutch teeth 26a and has an external conical friction surface 28a, corresponding to the elements 28 and 28 on adjunct 24 integral with gear 22.

The body of gear 52 andadjunct 24a with clutch teeth 26al and external friction cone 28a constitute one-half of a synchronizing coupling means to establish the transmission in second speed ratio.

In order to lock shaft 30 either to the main clutch shaft 20 for direct, high speed driving, or to the gear 52 for second speed driving, a positive coupling element 60 is slidably keyed to shaft 30 between the gears 22 and 52. Coupling element 60 has external gear-like clutch teeth 62 at its forward end adapted to interlock with the internal gear-like clutch teeth 26 on the part 24 rigid with gear 22. External gear-like clutch teeth 62a on its rearward end are adapted to interlock with internal gear-like clutch teeth 26a. on part 24a rigid with gear 52. When coupling element 60 is moved forward teeth 62 interlock with teeth 26 with the result that shaft 30 is locked to the gear 22 and main clutch shaft 20 to couple the transmission in third speed. When coupling element 60 is moved rearward teeth 62a interlock with teeth 26a with the result that gear 52 becomes locked to shaft 30 so that the transmission is coupled in second speed.

Coupling element 60 is formed midway between its ends with a radially extending circumferential iiange 64. Longitudinal openings spaced (in the form of the invention illustrated) 120 apart, extend from end to end. These openings consist of preferably round holes 66 in the region of the flange 64 and grooves 68 in the body of element 60 coaxial with the holes. Between the ends of the openings where the grooves become merged in the holes are annular ribs 10 with beveled sides '|2 so that the ribs 10 taper from base to crown in radial section. The holes 66 therefore are countersunk and have conical entrances on both sides of a plane normal to the axis and passing through the rib 10.

By reason of the interruptions in circumferential continuity due to grooves 68, the external clutch teeth 62 and 62a occur in three groups equi-angularly spaced as shown in Fig. 4.

Cooperating with the conical friction surface 28 of annular adjunct 24 rigid with gear 22 is an annular drum or cupped friction clutch element 80 having secured within` its flange 82 an internally coned friction ring 84 adapted to be engaged with the conical surface 28 on adjunct 24 integral with gear 22. Another similar drum or cupped friction clutch element 80a carries secured within its flange 82a, asimilar friction ring 84a adapted to engage over the conical surface 28a on part 24a of gear 52. Each cupped friction clutch element 80 and 80a is of ring-like form and composed of flanges at right angles one to the other and with tongues 86 and 66a extending radiallyinward at angularly separated regions corresponding to the positions of grooves 68 in positive coupling element 60 and reaching into said grooves. The drums or friction clutch elements 80 and 80a are united rigidly so as to move as one body by pins, bars, rods or the like 90 fixed at the front ends to tongues 86, and

' at their rear ends to tongues 86a. In the embodiment illustrated the ends of the pins 80 are shown .as riveted to the tongues as indicated at 92 and, 82a. Pins 90 are preferably' round in cross section. Between'its ends each pin is reduced in diameter to form spaced shoiilders preferably beveled as shown at 94 at an angle to the axis that is substantially the same as that of the bevel surfaces 12 on the sides of ribs 10 which bound the central portion of holes 66 in positive coupling element 60. The reduced central portions of pins 90 are so disposed with respect to the ribs T0, bounding the holes 66 in positive coupling element 60, that the center planes of said I'lbs, respectively, are equally spaced from the beveled shoulders 94 on the respective pins, when the transmission is in neutral with respect to second and third speeds.

'I'he friction clutch elements 80, 80a with their connecting pins are capable of very slight endwise movement, merely sufficient to squeeze out the oil lm present when second and third trains are in neutral, as illustrated in Fig. l, and on' which film oi' oil the elements ride without substantial friction under these conditions, and are also capable of a limited angular movement relative to coupling element 60, as permitted by the differences in diameter of the grooved portion of pins 90 and of the holes 66.

The friction clutch elements are normally centered or brought to and retained in neutral position when coupling element 60 is in neutral by the elastic force of plungers |00, which are urged radially inward by coil springs |02, since the ends of said plungers are conoidal as indicated at |04 and are of a s ize and contour to fit neatly between the beveled shoulders 94 on pins or rods 910. Plungers |00 slide in inverted cylindrical cups |06 fitted into radial holes drilled into the iiange 64 of slidable coupling element 60 and opening into the holes 66 at right angles to the axes of the latter. Each cup is keyed in place by a'pin or key |08 and each has a vent hole at ||0 to permit free movement of the plungers.

'I'he control mechanism shown in Figs. 1 and 4 comprises two shifter rails or bars and ||2 that can be selectively operated in a known manner by the manipulation of shift lever H4. In this form of control a yoke ||6 (Fig. 1) slidable with rail engages a circumferential groove in a hub formed on gear and may slide the latter into mesh with countershaft gear 46 to connect the first speed train with the shaft 20, or into mesh with the reverse idler for reverse driving. i

A yoke ||6 is mounted on rail ||2. Yoke ||8 is equipped with grooved shoes |20 each shaped to embrace the rim of flange 64. The shoes arc disposed at opposite ends of a diameter or `aid iiange 64 in order to apply balanced pressure to slide the coupling element so as to move its teeth into and out of engagement with the clutch teeth 26 or 26a. A curved arm |22 on yoke ||8 extends rearward and upward above the rail ||2 and its end is grooved vertically, as indicated at |24 in Fig. 2, to receive the lug or stud 26 fixed to shift lever ||4 between the fulcrum of this lever and the lower end |28 in substantial accordance with patent to P. L. Tenney No. 1,886,850, November 8, 1932.

By moving the shift lever |4 sidewise so that its lower end |28 becomes engaged with the usual notch provided for the purpose in the inner side of rail a shift may be made from neutral to rst speed or to reverse. By moving the shift lever sidewise in the opposite sense the stud |26 may be caused to engage in the slot |24 of arm |22 and the coupling element 60 may be slid forward to engage clutch teeth 26 and thereby couple the transmission in third speed or high, or the coupling element 60 may be slid rearward into engagement with teeth 26a and thereby bring into operative condition the second speed train.

As the yoke ||8 moves forward the spring pressed plungers |00 move the pins or bars 90, and the friction clutch drums 80, a, forward Y together more tightly with a force sufcient to produce enough .pressure between the internally-conical surfaced friction ring 84 and the externally conical surface 28 on gear 22 to cause alight frictional coupling sufficient, if there is a difference of speed between gear 22` andfshaft I8, to move the clutch drums angularly -in one sense or the other, until the beveled surfaces 12 on the coupling element 60 and the-beveled shoulders 94 on the rods 80 are in: alinement as shownin Figs. 5 and 6. Then continued pressure upon the shiftlever tends to force the friction surfaces thus-increasing the tendency to equalize the velocities of gear 22 and shaft 30. And when these velocities are equalized the resistance caused by inertia of the differentially rotating parts disappears and the teeth 28 and 62 may be intermshed without clashing. A similar action takes place when yoke ll I8 is moved rearward to couple the'secnd speed train.

Synchronizing mechanisms of this type opcrate on the principle af-th Anm-t Patent No.

1,866,614, patented July '1`2, 1932. They arel sometimes known as inertia check" synchronizers because of the resistance to meshing of the positive clutch elements interposed by the friction clutch elements throughthe inclined .checking surfaces such'ia I2vand .684, which oppose a resistance to 'axiaiginovement of the axially movable positive clutch element proportional to the difference` in speed of the parts to be coupled. The vspring-pressed plunger functions as a priming pr..cocking device, since it insures alinement "of the checking surfaces as soon as the slidable/positive coupling element begins a movement as disclosed in Tyler patent', January 5,1932.

1. In variable speed power transmission mech anism, the combination of a-shaft; axially spaced and axially xed positive clutch elements capable of rotation independently of said shaft around the axis thereof; a positive coupling ele- Beissue No. 18,319,

, ment slidably keyed to' said shaft and adaptedY to be interlocked selectively with either of said axially fixed positive clutch elements,l said slidable coupling' element having openings parallel with the axis of the shaft; friction clutch elements rigid with said axially xed positive clutch elements; axially movabl'efriction clutch elements arranged to coo rate with said axially to interlock with its companion,

xed friction clutch elements; pins rigidly connecting said ments, said pins extending through the openings in theslidabl'e positive coupling element each pin havingv spaced checking shoulders for cooperating with the edges of said openings, the cross-sectional dimensions of the pins Vbetween the spaced checking that of the openings pling element.

2. The mechanism dened in claim 1 in combination with elastic yieldable means arranged to temporarily connect the slidable positive elevment with the axially movabley friction clutchelements.

3. The mechanism defined in claim 1 in combination with elastic yieldable means carried by the slidable positive coupling element and yieldably engaging said pins between the spaced checking shoulders to temporarily connect the slidable positive coupling element with the axially movable friction clutch elements;

4. Variable speed power transmission mecha- 'mounted in the slidable couplingv element, said plungers having conical ends adapted to yieldably engage the pins of the axially movable friction clutch elements between thebeveled shoulders.

6. `Variable speed power nism'as defined in claim 1 coupling element slidably transmission mechain which the positive keyed to the shaft is axially movableA friction clutch eleshoulders being less than. in the slidable positive cou-A i nism as defined in claim 1,- wherein the openings provided at each endV with a group of clutch I teeth and with a circumferential flange disposed between the groups of clutch teeth, said openings through which the pins connecting said axially movable friction-clutch elements pass being in the flange.

. EARL A. THOMPSON'. 

